How to create Search Functionality using Optional Parameter in Spring Boot-CodePudding

I want to build a search functionality in my application. There are many parameters which can be optional.

Model

@Getter
@Setter
@EqualsAndHashCode(exclude = "inventoryInspectionReport")
@NoArgsConstructor
@Entity()
public class Inventory {
    @SequenceGenerator(
            name = "car_inventory_sequence",
            sequenceName = "car_inventory_sequence",
            allocationSize = 1
    )
    @Id
    @GeneratedValue(
            strategy = GenerationType.SEQUENCE,
            generator = "car_inventory_sequence"
    )
    private Long id;
    @Column(nullable = false)
    private String name;
    @Column(nullable = false)
    private String owner;
    @Column(nullable = false)
    private String km_driven;
    @Column(nullable = false)
    private Integer price;
    @Column
    private String fuelType;
    @Column
    private String location;
    @Column
    private String insuranceValidity;
    @Column
    private String rto;
}

Controller

@GetMapping("/buy-car")
    public String showBuyCarPageList(Model model,
                                     @RequestParam("page") Optional<Integer> page,
                                     @RequestParam("size") Optional<Integer> size
    ){
        int currentPage = page.orElse(1);
        int pageSize = size.orElse(16);
        Page<Inventory> pageObj = carInventoryService.listAllCarIfShow(currentPage, pageSize);
        int totalPages = pageObj.getTotalPages();
        long totalItems = pageObj.getTotalElements();
        List<Inventory> carInventoryList = pageObj.getContent();

        model.addAttribute("currentPage", 1);
        model.addAttribute("totalPages", totalPages);
        model.addAttribute("totalItems", totalItems);
        model.addAttribute("carInfo", carInventoryList);

        return "frontend/buy-car-list";
    }

@Service
@AllArgsConstructor
public class InventoryServiceImpl implements InventoryService {

    @Autowired
    private Environment env;
    InventoryRepository carInventoryRepository;
    InventoryImagesRepository carInventoryImagesRepository;

    @Override
    public Page<Inventory> listAllCarIfShow(int pageNumber, int pageSize) {
        Pageable pageable = PageRequest.of(pageNumber - 1, pageSize);
        return carInventoryRepository.findAllByShow(true, pageable);
    }
}

My question is, how i can create a search functionality? There can be some parameter null? How i can query or ignore the parameters?

Bellow is query samples

http://localhost:8080/buy-car?page=1&size=1&name=Car2
http://localhost:8080/buy-car?page=1&size=1&name=Car2&owner=1st
http://localhost:8080/buy-car?page=1&size=1&fuelType=Petrol&owner=1st

Sample form image

CodePudding user response：

Assuming that you are using JPA. You can handle it by writing a query as below. This will ignore the where condition if the parameter is null.


@Repository
public class InventoryRepository extends JPARepository<Inventory, Long> {

    @Query("SELECT i FROM Inventory i WHERE (:name is null or i.name = :name) and (:owner is null or i.owner = :owner)")
    Page<Inventory> findAllByShow (String name, String owner, Pageable pageable);
}

PS: You need to update your Controller and Service layers to accept other parameters such as name, owner etc..